There are 4 tiers of punishments:
1.) 10 game chat restriction
2.) 25 game chat restriction
3.) 14 day ban
4.) Permanent ban
You start at tier 1 and every subsequent offense moves you up one tier (though it is possible to drop tiers if you go long enough without a punishment). So, if you have recently received a 14 day ban, then I'm sorry to say that you're not going to get the permanent ban lifted. A permanent ban is the next step after the 14 day ban, and you're even warned when you get the 14 day ban that your next punishment would be a permanent ban. At this point, you've already received multiple chances to change your behavior, and you refused to do so.
If you haven't received a 14 day ban recently, then it might be possible to have your punishment reduced, but you will need to contact Player Support and ask them about it. If they say no, then you're out of luck.